Step 1

Combine the pasta, cherry tomatoes, onion, olives, oil, garlic, red chile flakes, 1/2 teaspoon salt, and several grinds of black pepper in the pot. Add 2 3/4 cups water and stir to combine. Place the tuna on top of the pasta mixture but do not submerge it.

Step 2

Lock on the lid, select the Pressure Cook function, and adjust to Low pressure for 6 minutes. Make sure the steam valve is in the “Sealing” position and that the “Keep Warm” button is off.

Step 3

While the pasta is cooking, stack the basil leaves, roll them up tightly as you would a sleeping bag, and slice crosswise into thin ribbons.

Step 4

When the cooking time is up, quick-release the pressure. Remove the lid. Add the basil, lemon zest, and lemon juice to the pot and stir, breaking up the fish into bite-size chunks. Season with salt and black pepper.

Step 5

Let the pasta stand in the pot set in the appliance, uncovered, for 5 minutes to allow the sauce to thicken before serving.